Food poisoning is one of the most serious public health problems everywhere around the world. Various harmful additives or contaminants in food may affect the health of the general public. Therefore, the quality of food must be regularly examined to ensure that some poisonous or hazardous substances do not exceed safety levels.
The concentration of these harmful substances may be determined by using testing agents. The traditional chemical testing approaches are time consuming and may not respond promptly. Alternatively, material characterization techniques in laboratories may be used to analyse the concentration of a target substance and even the composition of a testing sample. Although the results may be very accurate and sensitive, these techniques used in laboratories may not be suitable for daily applications which require prompt and low-cost testing results.